A contact that electrically connects to each other electrical circuits or the like of wiring boards disposed to be opposed to each other is generally known. Examples of such a contact are ones described in Patent Document 1 and Patent Document 2.
A contact 1 in Patent Document 1 includes two contact pins 2 having equal shapes and a coil spring 3 as shown in FIGS. 2 and 3.
The contact pin 2 mainly includes locking claws 4, a locking hole 5, a flange portion 6, and a pin tip end portion 2A. Two locking claws 4 are provided to be opposed to each other and are supported by resilient supporting bar portions 4A. This allows the two locking claws 4 to approach to and separate from each other. The locking hole 5 is a hole in which the locking claws 4 are fitted and is formed in a rectangular shape so as to be matched with the width of each locking claw 4. Thus, by making the two contact pins 2 opposed to each other to be displaced by 90 degrees and fitted in each other, two pairs of locking claws 4 are respectively locked in the openings of the locking holes 5 to be prevented from falling off. The flange portion 6 is a part on which the coil spring 3 is to abut. By making the two contact pins 2 displaced by 90 degrees and fitted in each other in a state of being inserted in the coil spring 3, both ends of the coil spring 3 abut on the respective flange portions 6 to assemble the contact 1. Both ends of the contact 1 assembled in a state where the two contact pins 2 are fitted in each other are the pin tip end portions 2A that contact electrodes or the like and are electrically connected to them.
Also, a contact 7 in Patent Document 2 includes a plunger 8 and a spring 9 as shown in FIG. 4.
The plunger 8 is formed in an elongated plate shape and is provided at the upper portion with a broad portion 8A receiving the spring 9, and at the upper portion of this broad portion 8A is formed a terminal portion 8B contacting an electrode. At the lower portion of the broad portion 8A is formed a core bar portion 8C inserted in the spring 9 to be movable up and down. The spring 9 is formed to have an inside diameter that allows the core bar portion 8C to be inserted to be movable up and down. The lower end portion of the spring 9 is tapered to contact an electrode or the like.
Also, there is one having a structure as in Patent Document 3. A socket for an electrical component in Patent Document 3 has a contact member contacting a terminal of an electrical component, a board conducting member made of a conductive plate material and connected to a printed circuit board, and a coil spring disposed between the contact member and the board conducting member for conduction between them. The contact member and the board conducting member do not contact each other and are connected with the coil spring in-between.    Patent Document 1: Japanese Patent National Publication No. 2008-516398    Patent Document 2: Japanese Patent Laid-Open No. 2004-152495    Patent Document 3: Japanese Patent Laid-Open No. H11-317270